At low concentrations, how does carbon dioxide affect the central nervous system?

Carbon dioxide has a complex relationship with the central nervous system, and at low concentrations, it primarily acts as a stimulant. When CO2 levels increase in the blood, even slightly, the body senses this change and triggers a response. The central nervous system reacts by stimulating respiratory centers in the brain to increase respiration rate, which in turn helps to expel excess CO2 and maintain proper pH levels in the body. This stimulation can lead to increased alertness and a heightened state of awareness.

In contrast, the effects at higher concentrations can lead to respiratory depression and other negative outcomes; however, at low levels, the predominant action is one of stimulation. This dynamic is especially important in understanding how the body regulates breathing and maintains homeostasis in response to varying levels of carbon dioxide in the environment.